In recent years, there has been increasing interest in inflatable boats because of their inherent advantages, including convenience, portability and safety. In the case of inflatable runabouts, all prior boats have relied upon some form of rigid bottom such as shown in U.S. Pat. No. 3,694,836 and 3,812,805, to which the inflatable side tubes are attached, or to some form of detachable floorboards or stiffening devices which must be separately inserted into the boat and joined by various means, as disclosed in U.S. Pat. No. 3,566,425. In the case of the former, the portability of the boat is seriously limited by the size and weight of the rigid bottom, whether comprised of one or more parts or sections. Therefore, boats of this character are not truly collapsible. In the case of the latter, the ease and convenience of use is adversely affected by the required assembly functions and by the separate parts which can be lost or damaged.
Because of the hydrodynamic forces exerted upon the hull of a boat when displacement speeds are exceeded, the hull must achieve a relatively high degree of rigidity. Without such rigidity, the hull can be deformed by these hydrodynamic forces to such a degree that it will not properly rise over the bow wave that is created in the water by the forward motion of the boat. Prior art collapsible, inflatable runabouts as exemplified by U.S. Pat. No. 3,261,038, have relied upon some means of creating a modified vee bottom between the inflatable side tubes consisting of coated fabric stretched into the desired shape by a rigid or inflatable keel which is, in turn, supported by a floorboard assembly. Thus the shape of the bottom planing surface of the boat and therefore the performance of the boat is largely dependent upon the keel and floorboard assembly.
Another characteristic of all prior collapsible, inflatable runabouts is that the bottom of the cockpit is located near or below the bottom of the inflatable tubes and is below the waterline of the boat when the boat is in use. Therefore, water which enters the boat due to rain, spray or other causes, will collect inside the cockpit unless removed by the occupants of the boat. Although some inflatable runabouts are equipped with devices referred to as self-bailers, these devices will drain water from the cockpit only when the boat is moving through the water at relatively high speed. In rough water conditions or at other times when high speed is impossible or impractical, the comfort of the occupants and the performance of the boat can be adversely affected by water collecting inside the cockpit of the boat.